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United States Patent |
5,298,823
|
Johnsen
|
March 29, 1994
|
Main field winding and connections for a dynamoelectric machine
Abstract
An improved rotor for a dynamoelectric machine which includes a rotor core
of magnetizable material having a longitudinal axis and axially spaced
core ends, winding end supports of electrically insulating material at the
core ends, and a winding having a plurality of layers of continuously
connected turns of wire and first and second exciter lead portions at
electrically opposite ends of the winding. The first exciter lead portion
includes a crossover section oriented generally transverse to the
longitudinal axis and located at one of the core ends. The winding is
oriented generally parallel to the longitudinal axis and extends around
the core, over the crossover section of the first exciter lead portion of
the winding, and over both winding end supports, forming a plurality of
end turns at the core ends and thereby maintaining the core and the
winding end supports fixed relative to each other and constraining the
crossover section of the first exciter lead portion between the end turns
and the winding end support. A slot and a recessed area are incorporated
into the winding end support, with the slot allowing the crossover section
of the first exciter lead portion of the winding to be conveniently routed
between the end turns and the winding end support, and the recessed area
providing constraint for the end turns, thereby preventing deformation of
the end turns due to centrifugal forces incident with rotation of the
rotor.
Inventors:
|
Johnsen; Tyrone A. (Rockford, IL)
|
Assignee:
|
Sundstrand Corporation (Rockford, IL)
|
Appl. No.:
|
940423 |
Filed:
|
September 4, 1992 |
Current U.S. Class: |
310/71; 310/194; 310/214; 310/261 |
Intern'l Class: |
H02K 011/00; H02K 003/48 |
Field of Search: |
310/71,194,214,216,261,270,179,180
|
References Cited
U.S. Patent Documents
3292025 | Dec., 1966 | Victor | 310/208.
|
4217515 | Aug., 1980 | Long et al. | 310/270.
|
4562641 | Jan., 1986 | Mosher et al. | 310/270.
|
4583696 | Apr., 1986 | Mosher | 310/270.
|
4598223 | Jul., 0186 | Glennon et al.
| |
4603274 | Jul., 1986 | Mosher | 310/270.
|
Foreign Patent Documents |
2905639 | Aug., 1979 | DE | 310/214.
|
0006069 | Jan., 1983 | JP | 310/261.
|
0185031 | Aug., 1986 | JP | 310/261.
|
Primary Examiner: Skudy; R.
Assistant Examiner: To; E.
Attorney, Agent or Firm: Crowe; Lawrence E.
Claims
I claim:
1. A precision wound rotor comprising:
a magnetic core having a longitudinal axis and axially spaced core ends;
and
a winding having a plurality of continuously connected turns of wire, with
said turns of wire extending around the core in an axial direction and
forming a plurality of end turns at the axially spaced core ends;
said winding further having at a one electrical end thereof an exciter lead
portion, whereby the winding may be connected to a source of electrical
power;
said exciter lead portion including a crossover section oriented in a
direction generally mutually transverse to the axis and to the end turns,
with said crossover section being disposed between the end turns and one
of the core ends, the end turns thereby constraining the crossover section
between the end turns and the one of the core ends.
2. A precision wound rotor comprising:
a magnetic core having a longitudinal axis and axially spaced core ends;
a winding end support made of electrically insulating material at one of
the core ends; and
a winding having a plurality of continuously connected turns of wire, with
said turns of wire extending around the core and over the winding end
support in a generally axial direction, with said turns of wire forming a
plurality of end turns extending transverse to the axis across the winding
end support and constraining the winding end support against the one of
the core ends;
said winding further having at one electrical end thereof an exciter lead
portion, whereby the winding may be connected to a source of electrical
power;
said exciter lead portion including a crossover section oriented in a
direction generally mutually transverse to the axis and to the end turns,
with said crossover section being disposed between the end turns and the
winding end support, the end turns thereby constraining the crossover
section between the end turns and the winding end support.
3. A precision wound rotor, according to claim 2, wherein the plurality of
turns of said winding form a plurality of layers of end turns at the core
ends.
4. A precision wound rotor, according to claim 2, further comprising:
a slot in a surface of the winding end support wherein the exciter lead
portion of the winding may be routed between the end turns and the winding
end support, the slot thereby allowing the exciter lead portion of the
winding to be recessed at least partially below the surface of the winding
end support.
5. A precision wound rotor, according to claim 2, wherein the exciter lead
portion is terminated in a lug, and wherein a surface of the winding end
support includes a relief and a groove extending across the surface of the
winding end support in a manner allowing the exciter lead portion and the
lug to be recessed at least partially below the surface of the winding end
support.
6. A precision wound rotor, according to claim 2, further comprising:
a recessed area in said winding end support configured and located such
that the end turns are constrained within said recessed area, thereby
preventing deformation of the end turns due to centrifugal forces incident
with rotation of the rotor.
7. A precision wound rotor according to claim 4, wherein said core is
configured generally as an elongated right circular cylinder and includes
oppositely opening longitudinally oriented recesses, thereby resulting in
the core having substantially an I-shaped cross-section, said recesses
having a flat lower surface and sidewalls oriented substantially
perpendicular to the lower surface.
8. A precision wound rotor, according to claim 7, wherein said winding end
support is configured generally as a flat plate having oppositely facing
first and second surfaces and a periphery matched to the I-shaped
cross-section of the core and also having said first surface configured as
a flat base whereby the winding end support facially engages the one of
the core ends.
9. A precision wound rotor, according to claim 8, wherein said recessed
area in the winding end support has a bottom surface parallel to the base
and walls perpendicular to the base, said recessed area being equal in
width to the recesses in the core and oriented such that, with the base of
the winding end support facially engaging the one of the core ends, and
the periphery of the winding end support aligned with the I-shaped
cross-section of the core, the recessed area of the winding end support,
in conjunction with the recesses in the core, form a channel for receipt
of the winding.
10. A precision wound rotor, according to claim 9, wherein the winding end
support includes a slot which extends along an intersection of a plane
defined by the bottom surface of the recessed area in the winding end
support with a plane defined by the lower surface of one of the recesses
in the core, said slot being configured as an inverted corner extending
along said intersection.
11. A precision wound rotor, according to claim 10, wherein the crossover
section of the exciter lead portion of the winding is positioned within
the slot in the winding end support, and the end turns are contained
within the recessed area of the winding end support at the one of the core
ends, said end turns thereby constraining the crossover section of the
exciter lead portion of the winding within the slot.
12. A precision wound rotor, according to claim 11, wherein the exciter
lead portion is terminated in a lug, and wherein the second surface of the
winding end support includes a relief and a groove, with the groove
extending from the relief across the second surface of the winding end
support and along one of the walls of the recessed area of the winding end
support in a manner allowing the exciter lead portion of the winding to be
routed past the end turns in a manner allowing the exciter lead portion
and the lug to be recessed slightly below the second surface of the
winding end support.
13. A precision wound rotor comprising:
a magnetic core having a longitudinal axis and axially spaced core ends;
a winding end support made of electrically insulating material at one of
the core ends;
a winding having a plurality of continuously connected turns of wire, with
said turns of wire extending around the core and over the winding end
support in a generally axial direction with said turns of wire forming a
plurality of end turns extending transverse to the axis across the winding
end support and constraining the winding end support against the one of
the core ends;
said winding further having at one electrical end thereof an exciter lead
portion terminating in a lug whereby the winding may be connected to a
source of electrical power;
said winding end support including in a surface thereof a groove and a
relief for receipt respectively therein of the exciter lead portion and
the lug, the groove and the relief thereby providing means by which the
exciter lead portion and the lug may be at least partially recessed below
the surface of the winding end support.
14. A precision wound rotor, according to claim 13, wherein said core is
configured generally as an elongated right circular cylinder and includes
oppositely opening longitudinally oriented recesses, thereby resulting in
the core having substantially an I-shaped cross-section, said recesses
having a flat lower surface and sidewalls oriented substantially
perpendicular to the lower surface.
15. A precision wound rotor, according to claim 14, wherein said winding
end support is configured generally as a flat plate having oppositely
facing first and second surfaces and a periphery matched to the I-shaped
cross-section of the core and also having said first surface configured as
a flat base whereby the winding end support facially engages the one of
the core ends.
16. A precision wound rotor, according to claim 15, wherein the second
surface of the winding end support further includes a recessed area for
receipt therein of the end turns of the winding with said recessed area
having a bottom surface parallel to the base and walls perpendicular to
the base, said recessed area being equal in width to the recesses in the
core and oriented such that, with the base of the winding end support
facially engaging the one of the core ends, and the periphery of the
winding end support aligned with the I-shaped cross-section of the core,
the recessed area of the winding end support, in conjunction with the
recesses in the core, form a channel for receipt therein of the winding.
17. A precision wound rotor, according to claim 16, wherein the relief is
located in the second surface of the winding end support, and the groove
extends from the relief across the second surface and along one of the
walls of the recessed areas in the winding end support, thereby allowing
the exciter lead portion of the winding to be conveniently routed past the
end turns of the winding.
Description
FIELD OF THE INVENTION
This invention relates to dynamoelectric machines, and more particularly to
a unique construction for orienting and terminating windings on rotors
utilized in such machines.
BACKGROUND OF THE INVENTION
The power density, reliability, and cost of a dynamoelectric machine are
directly related to the physical size and complexity of the machine.
Accordingly, manufacturers of dynamoelectric machines continually strive
to reduce the complexity and physical size of their machines in an attempt
to improve power density, provide enhanced reliability, and reduce cost.
Design improvements allowing reductions in the axial length and the
complexity of rotors used in dynamoelectric machines are of particular
interest in this regard. During operation, the rotor and associated
support structures are subjected to high centrifugal forces and bending
movements caused by rotation of the rotor and high internal magnetic
fluxes incident with operation of the dynamoelectric machine. This is
particularly true in dynamoelectric machines designed for use in aircraft
which typically operate at high rotational speeds and utilize very high
magnetic flux densities in order to achieve maximum performance with a
machine of minimum size and weight.
As the axial length of the rotor is decreased, problems associated with
critical speed and bending of the rotor are also diminished. This in turn
allows reduction in the size of structural elements comprising the rotor
and corresponding reduction in the size of structures supporting the
rotor. It will be appreciated, therefore, that, as a result of reductions
in the size of structural elements comprising and associated with the
rotor, reduction in the axial length of the rotor will allow an overall
reduction in the size of the dynamoelectric machine greater than would
have been derived solely from the reduction in axial length of the rotor
alone.
As complexity of the rotor is decreased, size and cost of the rotor also
decrease. As a result, rotor designs comprised of a minimal number of
simple parts are highly desirable.
Through the years, designers and manufacturers of dynamoelectric machines
have devoted considerable effort toward advancing the state of the art in
the design and manufacture of dynamoelectric machines in general, and more
specifically toward reduction in the axial length and complexity of the
rotors utilized in these machines. Typical of these past efforts are U.S.
Pat. No. 3,292,025 to Victor; U.S. Pat. No. 4,217,515 to Long et al; U.S.
Pat. No. 4,598,223 to Glennon et al; U.S. Pat. No. 4,603,274 to Mosher.
U.S. Pat. No. 3,292,025 to Victor describes a rotor end winding having a
special conductor configuration in an end turn region of a rotor in
conjunction with a special coil-to-coil connector which allows a radial
transition to be made between coils in the end turn region, thereby
removing the necessity for an overlapping or extra conductor layer.
The Victor patent is directed to connections between coils in a rotor
having a winding made up of multiple separate coils, whereas the present
invention, to be described hereinafter, utilizes a rotor having a winding
formed as a single continuous coil, and does not, therefore, require
coil-to-coil connectors. In addition, the present invention addresses
configuration and termination of the exciter lead portions of the winding,
whereas Victor addresses only coil-to-coil connections and does not
address the exciter lead portions of the windings.
And finally, Victor states that an object of his invention is to provide an
arrangement "which does not employ extra turns or overlapping turns at the
end of the rotor", thereby specifically teaching away from the present
invention which is directed in part to defining a manner in which the
exciter lead portion of the winding can be conveniently crossed underneath
the winding at the core ends.
U.S. Pat. No. 4,217,515 to Long et al describes means for embedding end
turns of field windings for a rotor in the rotor and restraining the field
windings in the rotor by use of wedge means. The rotor of the present
invention, to be described hereinafter, utilizes a construction radically
different from Long, particularly with regard to placement and support of
end turns and the method utilized to restrain the windings.
U.S. Pat. No. 4,598,223 to Glennon et al, assigned to the assignee of the
present invention, describes a unique construction for the end turns of
stator windings in dynamoelectric machines and is directed to an improved
stator end turn construction which provides capability for enhanced
cooling and/or a reduction in axial length of the machine. The Glennon
patent is directed specifically to stator end turns and does not address
the rotor or end turns of windings in a rotor.
U.S. Pat. No. 4,603,274 to Mosher, also assigned to the assignee of the
present invention, describes a structure for facilitating precision
machine winding of a rotor for a high speed machine and a method of
producing a rotor utilizing the structure as defined. Mosher utilizes an
insulator having radially spaced rows of notches for guiding turns of a
winding to predetermined locations in a precision wound rotor. Wedges are
attached following winding to prevent distortion of the winding due to
centrifugal forces incident with rotation of the rotor.
Mosher is of special interest because both Mosher and the present invention
incorporate structures made from insulative material at each core end,
these structures being specifically denoted as an "insulator", according
to Mosher, and as the "winding end support" in the present invention.
However, the configuration and functions performed by the winding end
support of the present invention, described hereinafter, are significantly
different from the configuration and function of the insulator of Mosher.
In light of the following description of the present invention, it will be
readily appreciated that the present invention is clearly patentably
distinct from, and constitutes significant improvement over, prior
dynamoelectric machines.
SUMMARY OF THE INVENTION
It is a principal objective of the invention to provide a new and improved
dynamoelectric machine. More specifically, it is an objective to provide
improvements in rotor construction which allow axial length of the
dynamoelectric machine to be reduced, and, in addition, allow such an
improved rotor to be manufactured at low cost from a minimal number of
simple parts.
An exemplary embodiment of the invention achieves the foregoing objectives
in a dynamoelectric machine incorporating a precision wound rotor. The
rotor includes a rotor core of magnetizable material having a longitudinal
axis and axially spaced core ends, winding end supports of electrically
insulating material at the core ends, and a winding. The winding is made
up of a plurality of continuously connected turns of wire and also
includes at electrically opposite ends a first and a second exciter lead
portion. The first exciter lead portion includes a crossover section
oriented generally transverse to the longitudinal axis and located at one
of the core ends. The plurality of layers of turns is oriented generally
parallel to the longitudinal axis and extends around the core, over the
crossover section of the first exciter lead portion of the winding, and
over both winding end supports, thereby maintaining the core and the
winding end supports fixed relative to each other and constraining the
crossover section of the first exciter lead portion between the winding
and the winding end support. The winding also forms a plurality of end
turns at the core ends. A slot is incorporated into the winding end
support, the slot being configured and located such that the crossover
section of the first exciter lead portion of the winding may be
conveniently routed between the winding and the winding end support. A
recessed area is also incorporated into the winding end support, the
recessed area being configured and located such that the end turns are
constrained within the recessed area, thereby preventing deformation of
the end turns due to centrifugal forces incident with rotation of the
rotor. Incorporation of the slot into the winding end support allows the
exciter lead portions of the winding to be conveniently crossed beneath
the winding in those instances where a particular winding configuration
would otherwise result in inconvenient location of the exciter lead
portions. One example of such an instance is a winding having an even
number of layers where it is desired to have the exciter lead portions of
the winding terminate at diametrically opposite positions with respect to
the longitudinal axis in a plane parallel to one of the core ends.
In a winding having an even number of layers, both exciter lead portions of
the winding would normally terminate on one side of the longitudinal axis
following fabrication of the winding. Prior to the addition of the slot of
the instant invention, one of the exciter lead portions of the winding had
to be crossed above the end turns of the winding in order to achieve the
desired diametrically opposite termination of the exciter lead portions
described in the preceding paragraph, thereby resulting in a rotor and
dynamoelectric machine having a greater axial length than a rotor and
dynamoelectric machine constructed according to the present invention.
The present invention also provides an additional advantage in that, with
the crossover section of an exciter lead portion of the winding routed
through the slot between the winding and the winding end support, the
crossover section of the exciter lead portion is constrained within the
slot by the winding, thereby preventing deformation of the crossover
section due to centrifugal forces incident with rotation of the rotor.
Prior to the addition of the slot of the present invention, additional
parts were required in order to constrain the crossover section of the
exciter lead portion of the winding. The slot of the present invention
eliminates the need for these additional parts, thereby decreasing
complexity and cost of dynamoelectric machines constructed according to
the present invention in comparison to prior dynamoelectric machines.
The present invention provides a further additional advantage in a
preferred embodiment by incorporating the recessed area into the winding
end support in order to provide support for the end turns. Prior to
incorporation of the recessed area into the winding end support, according
to the present invention, additional parts commonly referred to as end
turn support pieces were typically required in order to prevent
deformation of the end turns of the rotor due to centrifugal forces
incident with rotation of the rotor. The recessed area of the present
invention eliminates the need for these end turn support pieces, thereby
further decreasing complexity and cost of dynamoelectric machines
constructed according to the present invention in comparison to prior
dynamoelectric machines.
Other objectives and advantages will become apparent from the following
description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded three-dimensional perspective view of a shaft
assembly for a dynamoelectric machine embodying the invention;
FIG. 2 is a three-dimensional view of an embodiment of the rotor having an
even number of layers of turns of wire with the winding removed and
showing the configuration of the first exciter lead, including the
crossover section of the winding preformed to fit into the slot in the
winding end support of the preferred embodiment of the invention;
FIG. 3 is a shortened sectional view of the rotor of FIG. 2 taken along
line 3--3;
FIG. 4 is a sectional view of the rotor of FIG. 2 taken along line 4--4;
FIG. 5 is an end view of the rotor of FIG. 2 with the end turns removed in
order to clearly illustrate the crossover section of the first exciter
lead portion of the winding crossing beneath the winding via the slot in
the winding end support;
FIG. 6 is an end view of an embodiment of the rotor having an odd number of
layers of turns of wire.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is now made to FIG. 1 which depicts in an exploded
three-dimensional fashion the manner in which the rotor 10 is assembled
into an exemplary shaft assembly 50 for a dynamoelectric machine. As seen
in FIG. 1, the rotor 10, to be described more fully hereinafter, is
inserted into an elongated slot 54 in shaft 52 of the shaft assembly 50,
and secured therein by an interference fit between the assembled rotor 10
and shaft 52, and a cylindrical sleeve 56 which is installed over the
shaft 52 and rotor 10 by a process such as shrink fitting, thereby
completing fabrication of the shaft assembly 50.
Reference is now made to FIGS. 2 through 5, depicting a preferred
embodiment of a rotor 10, according to the present invention. Referring
first to FIG. 2, the rotor 10 includes a magnetic core 12, winding end
supports 18, 18a, and, as best seen in FIGS. 4 and 5, a winding 20.
The magnetic core 12, best seen in FIG. 2, has a longitudinal axis 14 and
axially spaced core ends 16, 16a. The core is configured generally in the
shape of an elongated right circular cylinder and incorporates oppositely
opening longitudinally oriented recesses 121, 121a, thereby resulting in
the core having substantially an I-shaped cross-section. Recess 121 has a
flat lower surface 122 and sidewalls 123, 124 oriented substantially
perpendicular to the lower surface 122. In similar fashion, recess 121a
has a flat lower surface 122a shown in cross-section in FIG. 4 and
sidewalls 123a, 124a (not shown) oriented substantially perpendicular to
the lower surface 122a.
Winding end supports 18, 18a, made of electrically insulating material,
shown in three-dimensional fashion in FIG. 2 and in cross-section in FIGS.
3 and 4, are utilized at each of the core ends 16, 16a of the rotor 10. As
best seen in FIG. 3, each of the winding end supports 18, 18a is
configured generally as a flat plate having oppositely facing first and
second surfaces 180, 180a and 181, 181a, respectively, and a periphery
matched to the I-shaped cross-section of the core 12. The first surfaces
180, 180a of the winding end supports 18, 18a are configured as flat bases
182, 182a, whereby the winding end supports 18, 18a facially engage the
core ends 16, 16a. As shown in FIG. 2, the second surfaces 181, 181a of
the winding end supports 18, 18a include recessed areas 32, 32a. Recessed
area 32 includes a bottom surface 320 parallel to the base 182 and walls
321, 322 intersecting with and perpendicular to the bottom surface 320.
Recessed area 32a includes a bottom surface 320a parallel to the base 182a
and walls 321a, 322a intersecting with and perpendicular to the bottom
surface 320a. The recessed areas 32, 32a are equal in width to the
recesses 121, 121a in the core 12 and oriented such that, with the bases
182, 182a of the winding end support 18, 18a facially engaging the core
ends 16, 16a, and the peripheries of the winding end supports 18, 18a
aligned with the I-shaped cross-section of the core 12, the recessed areas
32, 32a of the winding end supports 18, 18a in conjunction with the
recesses 121, 121a in the core 12 form a channel which extends entirely
around the rotor 10.
As shown in FIGS. 2 and 4, winding end support 18 also includes a slot 30.
The slot 30 is located along an intersection of a plane defined by the
bottom surface 320 of the recessed area 32 in winding end support 18 with
a plane defined by the lower surface 122 of the recess 121 in the core 12,
the slot 30 being configured as an inverted corner at the intersection of
the two planes.
The winding 20, as shown in FIG. 4, has a plurality of layers 22,
specifically designated as layers 22a, 22b, 22c, 22d, 22e, 22f in FIG. 4,
of continuously connected turns of wire 24 as shown in FIG. 3, with the
plurality of layers 22 of turns of wire 24 being tightly packed and
entirely contained within the channel, best seen in FIG. 2, formed by the
recessed areas 32, 32a in the winding end supports 18, 18a and the
recesses 121, 121a in the core 12. As shown in FIGS. 2 and 5, the winding
20 further has, at electrically opposite ends, a first exciter lead
portion 28 and a second exciter lead portion 29, both first and second
exciter lead portions being located at the same core end 16. The first
exciter lead portion 28 includes a crossover section 280 positioned within
the slot 30 in the winding end support 18. Referring now to FIGS. 4 and 5,
the layers 22 and turns of wire 24, which make up the winding 20, are
oriented generally parallel to the longitudinal axis 14 and extend around
the core 12, over the crossover section 280 of the first exciter lead
portion 28 of the winding 20, and over both winding end supports 18, 18a,
thereby maintaining the core 12 and the winding end supports 18, 18a fixed
relative to each other. As shown in FIGS. 3 and 4, the plurality of layers
22 of turns of wire 24 form a plurality of end turns 26, 26a entirely
contained within the recessed areas 32, 32a of the winding end supports
18, 18a at the core ends 16, 16a. The crossover section 280 of the first
exciter lead portion 28 of the winding 20 is, therefore, constrained
within the slot 30 in the winding end support 18 by the end turns 26 of
the winding 20.
As shown in FIGS. 2, 3, and 5, the first and second exciter lead portions
28, 29 of the winding 20 terminate in a first lug 34 and a second lug 35,
respectively. The first and second lugs 34 and 35 are disposed
substantially equidistant from the longitudinal axis along a radial line
passing perpendicularly through the longitudinal axis 14 at the same core
end 16 as the first and second exciter lead portions.
Referring now to FIGS. 2, 3, and 5, the second surface 181 of the winding
end support 18 includes reliefs 40, 41, and further includes grooves 36
and 37 which connect to the reliefs 40 and 41 respectively, with the
grooves 36, 37 running across the second surface 181 and continuing along
walls 321 and 322, respectively, of the recessed area 32 in the winding
end support 18, whereby the first and second exciter lead portions 28, 29
may be routed past the end turns 26 of the winding 20, and also thereby
allowing a portion of the first and second lugs 34, 35 to be recessed
slightly below the second surface 181 of the winding end support 18 within
the reliefs 40 and 41 respectively, as shown in FIGS. 2 and 3. The grooves
36, 37 and reliefs 40, 41 also provide support for the first and second
exciter lead portions 28, 29, thereby preventing deformation of the first
and second exciter lead portions due to centrifugal forces incident with
rotation of the rotor.
Referring now specifically to FIG. 5, it can be seen that the winding 20 of
the preferred embodiment utilizes an even number of layers, specifically
six layers designated 22a through 22f, of turns of wire 24. It can also be
seen that, for a winding as shown, wherein a first turn 241 is initiated
as shown in FIGS. 2 and 5, adjacent the sidewall 124 of the recess 121 in
the core 12, and the remainder of the turns of wire 24 are sequentially
wound around the rotor 10 abutting one another, first in layer 22a wound
across the lower surfaces 122, 122a of the recesses 121, 121a, and in
subsequent layers 22b through 22f wound back and forth across the recesses
121, 121a, the last turn of wire 242 will end on the same side of the
longitudinal axis 14 where the first turn of wire 241 was initiated
whenever the winding 20 has an even number of layers. It will be
appreciated that the crossover section 280 of the first exciter lead
portion 28 of the winding, particularly when practiced in conjunction with
the slot 30 in the winding end support 18 of the preferred embodiment of
the present invention, allows the first exciter lead portion 28 to be
conveniently crossed under the end turns 26 of the winding 20 and
terminated diametrically opposite the second exciter lead portion 29.
It will be further appreciated that, with the crossover section 280 located
within the slot 30, and thereby constrained beneath the end turns 26,
axial length of the rotor is not increased by the addition of the
crossover section, and additional hardware is not required to prevent
deformation of the crossover section 280 of the first exciter lead portion
28 of the winding 20 due to centrifugal forces incident with rotation of
the rotor, in contrast to prior rotor designs wherein a crossover section
was utilized but not constrained beneath the end turns. In similar
fashion, with the end turns 26, 26a contained within the recessed areas
32, 32a in the winding end supports 18, 18a, additional hardware, such as
separate end turn support pieces utilized in prior rotor designs, are not
required in a rotor, according to the present invention, in order to
prevent deformation of the end turns 26, 26a due to centrifugal forces
incident with rotation of the rotor 10.
Although the preferred embodiment given hereinbefore with reference to FIG.
5 utilized a rotor 10 having a winding 20 including an even number of
layers 22 of turns of wire 24, it will be appreciated that the various
features of the invention may be practiced with advantage, either
independently or when combined in a manner differing from the preferred
embodiment, in other embodiments such as the rotor 10 illustrated in FIG.
6 which utilizes a winding 20 having an odd number of layers 22 of turns
of wire 24. The embodiment as depicted in FIG. 6 is identical to the
preferred embodiment except for the aforementioned difference in the
number of layers 22 of turns of wire 24, and the elimination of the
crossover section 280 of the first exciter lead portion 28 of the winding
20 and the slot 30 for receipt of the crossover section 280 in the winding
end support 18, since neither the crossover section 280 nor the slot 30
are required in an embodiment of the invention having an odd number of
layers 22 of turns of wire 24.
From the foregoing description, it is apparent that the invention described
provides an improved rotor for a dynamoelectric machine in which novel
features, such as locating the crossover section of the first exciter lead
portion of the winding between the winding and the core end or winding end
support, and incorporation of the slot, recessed areas, grooves, and
reliefs into the winding end supports, allow construction of a rotor
having a shorter axial length and reduced complexity when compared to
prior rotor designs, and, in addition, allow such an improved rotor to be
manufactured at low cost from a minimal number of simple parts. It is
further apparent that dynamoelectric machines utilizing a rotor, according
to the present invention, will offer increased power density and
reliability at lower cost than prior dynamoelectric machines as a result
of the shorter axial length and reduced complexity of the rotor, according
to the present invention.
Although this invention has been illustrated and described in connection
with the particular embodiments illustrated, it will be apparent to those
skilled in the art that various changes may be made therein without
departing from the spirit of the invention as set forth in the following
claims.
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